Energy Conversion and Management: X (Sep 2021)
Elucidating energy requirements for size reduction of malted maize, soybean and sorghum milling using attrition mill
Abstract
Malting involves controlled crop steeping, germination and kilning. Energy consumption patterns of milling malted maize, soybean and sorghum grains using attrition mill were investigated. The crops were conditioned to sprout for 24, 48, 72 and 96 h and dried at 60 °C for 18 h. Malted products were fed separately into attrition mill at 0.2, 0.4, 0.6, 0.8 and 1.0 kg/min. Inlet temperature of feed and machine parts, outlet temperature of flour produced and quantity of fuel consumed were recorded in each case. Standard equations were used to quantify energy input, intensity, output and efficiency, exergy loss and destruction. Energy input for milling malted crops germinated for 24, 48, 72 and 96 h respectively ranged from 0.283 to 0.881 MJ, 0.228–0.567 MJ, 0.193–0.578 MJ and 0.186–0.555 MJ for maize; 0.194–0.45 MJ, 0.254–0.379 MJ, 0.153–0.342 MJ and 0.184–0.36 MJ for sorghum, and 0.176–0.661 MJ, 0.373–0.562 MJ, 0.169–0.683 MJ and 0.189–0.617 MJ for soybean. Energy outputs increase with increase in feed rate. Energy utilization efficiencies of the operation ranged from 70.13 to 88.23% for maize, 71.90 to 91.94% for sorghum and 68.88 to 84.99% for soybean. Exergy loss and destruction of the malted crops were significantly different at p < 0.05. This study revealed that energy requirements for size reduction of malted maize, sorghum, and soybean depend on germination duration and feed rate. Attrition mill was appropriate for grinding malted maize, sorghum and soybean, and feed rate of 0.4 kg/h was recommended.
